Department of Energy Science and Engineering , DGIST , Daegu 42988 , Republic of Korea.
Analysis Research Division, Daegu Center , Korea Basic Science Institute , Daegu 41566 , Republic of Korea.
ACS Appl Mater Interfaces. 2018 May 9;10(18):16033-16040. doi: 10.1021/acsami.8b03285. Epub 2018 Apr 26.
Recently, black phosphorus (BP) with direct band gap exhibited excellent potential for optoelectronic applications because of its high charge carrier mobility and low dark current as well as the variable band gap of 0.3-1.5 eV depending on the number of layers. However, few-layer BP-based phototransistors (photo-FETs) have been limited in sensitivity and wavelength selectivity. To overcome the drawback of these photo-FETs, we studied hybrid photo-FETs combined with the novel properties of the two materials between the channel and sensitizer layers. By combining a strong absorbance of a quantum dot (QD) layer and a two-dimensional layer material with high carrier mobility, the hybrid photo-FETs are expected to produce high-performance photodetectors that can effectively control the responsivity, detectivity, and response time. In this study, we demonstrate that the photogenerated carriers formed from QD sensitizer layers migrate to the BP transport layer with high charge mobility and not only improve the photodetector performance but also enhance the photodoping effect of the BP transport layer with an ambipolar characteristic by electrons transferred from n-type CdSe QDs or holes injected from p-type PbS QDs. The responsivity and detectivity of hybrid BP/0D photo-FETs exhibit 1.16 × 10 A W and 7.53 × 10 Jones for the BP/CdSe QD photo-FET and 5.36 × 10 A W and 1.89 × 10 Jones for the BP/PbS QD photo-FET, respectively. The photocurrent rise (τ) and decay (τ) times were τ = 0.406 s and τ = 0.815 s for BP/CdSe QD photo-FET and τ = 0.576 s and τ = 0.773 s for BP/PbS QD photo-FET, respectively.
最近，具有直接带隙的黑磷 (BP) 因其高电荷载流子迁移率和低暗电流以及取决于层数的 0.3-1.5eV 的可变带隙而在光电器件应用中表现出优异的潜力。然而，基于少层 BP 的光电晶体管（photo-FET）在灵敏度和波长选择性方面受到限制。为了克服这些 photo-FET 的缺点，我们研究了结合了沟道和敏化层之间两种材料的新特性的混合 photo-FET。通过结合量子点 (QD) 层的强吸收和二维层材料的高载流子迁移率，混合 photo-FET 有望产生高性能光电探测器，可有效控制响应度、探测率和响应时间。在这项研究中，我们证明了来自 QD 敏化层的光生载流子迁移到具有高电荷迁移率的 BP 输运层，不仅改善了光电探测器的性能，而且通过从 n 型 CdSe QD 转移的电子或从 p 型 PbS QD 注入的空穴增强了 BP 输运层的光电掺杂效应具有双极性特性。混合 BP/0D photo-FET 的响应度和探测率分别为 BP/CdSe QD photo-FET 的 1.16×10 A W 和 7.53×10 Jones，以及 BP/PbS QD photo-FET 的 5.36×10 A W 和 1.89×10 Jones。光电晶体管的上升（τ）和下降（τ）时间分别为 BP/CdSe QD photo-FET 的 τ=0.406s 和 τ=0.815s，BP/PbS QD photo-FET 的 τ=0.576s 和 τ=0.773s。
